Alternating current motor for dry shavers or the like



Jan. 14, 1941. R KNAPP 2,228,663

ALTERNATING CURRENT MOTOR FOR DRY SHAVERS OR THE LIKE Filed May 51,19:58

' AWI/Zg/J UNITED. STATES PATENT OFFICE I ALTERNATIN G CURRENT MOTOR FORDRY SHAVERS OR THE LIKE Raymond Knapp, Long Island City, N. Y., assignorto Knapp-Monarch Company, St. Louis, Mo; a corporation of MissouriApplication May 31, 1938, Serial No. 210,992

3 Claims.

An object or my present invention is to provide a vibratory motor fordry shavers and the like adapted for silent operation on alternatingcurrent, the motor being comparatively simple and inexpensive tomanufacture.

, A further object is to provide a ,motor which eliminates allelectrical contacts and which eliminates all possibility ofmetallicparts of the motor striking each other thus making the motorentirely silent in operation.

A further object is to provide a motor comprising a casing, analternating current vibratory motor therein, blocks of rubber or thelike being strategically arranged relative to the operating arm of themotor and so shaped and arranged relative thereto that all clatteringnoise is elimi-'- nated and likewise vibrations intermediate the ends ofthe arm are damped out thus causing a very satisfactory and economicallyoperated motor for operating shearing heads of dry shavers or similardevices calling for reciprocating operation.

Still a further object is to provide a block of rubber or the like foreliminating noise of the operating arm of the motor and also-serving asa means to bias thrust pins against an inner shearing element to causeit toshearingly engage the outer shearing element.

Still another object is to provide an operating arm and an electromagnetso mounted within the casing that they may be relatively adjusted by anordinary screw driver to secure most efficient operation and to securesatisfactory operation at different voltages.

With these and other objects in view my invention consists in theconstruction, arrangement and combination of the various parts of mymotor, whereby the objects above contemplated are attained, ashereinafter more fully set forth,

pointed out in my claims and illustrated in the accompanying drawing.Although the invention is susceptible of a variety of embodiments, it isunnecessary to fully describe and illustrate more than one in order togive a full understanding of the invention both from its structural andfunctional standpoints. Accordingly, I have illustrated a preferred anddesirable embodiment thereof on the accompanying drawing, in which:

Figure 1 is a plan view of an alternating current motor for dryshavers-or the like embodyingmy invention, the device being shown on anenlarged scale, the cover member therefor being omitted and the upperend of the motor and shearing element associated therewith being shownin section.

Figure 2 is a sectional view on the line 2-2 of Figure 1. s

Figure 3 is a sectional view on the line 33 of Figure 2.

Figures 4 and 5 are perspective views of rubber I blocks or inserts usedin my motor; and

' Figure 6 is a sectional view on the line 6-8 of Figure 1. j

In the accompanying drawing I have used the reference character toindicate generally a casing for my motor. The casing C is formed in twoparts indicated as l0 and I2 in the drawing. The parts l0 and I2 areeach substantially onehalf 'of the casing C and are suitably secured to-,gether by three screws l3.

-Within the part III I provide a pair of shoulders or bosses l4 and Maon which is mounted a core comprising three legs l5, I6 and H. The corehas a connecting portion l8 and is preferably formed of laminations asshown in Figures'2 and 3 held together by rivets IS. The legs l6 and Hare provided with slots 20 through which screws 2| extend into theshoulders, and Ma.

An operating arm A is provided comprising an armature portion 22, an Lshaped bracket por- 'tion 23 and an armature extension 24. The

armature 22 is adapted to be periodically attracted toward the poles I5,I6 and ll of the electromagnet when a coil 25 on the center pole thereofis energized with alternating current. This will cause vibration of thearmature 22 since the bracket 23 being formed of resilient metal such asbrass or the like tends to return the armature 22 to the full lineposition illustrated as the alternating current recedes to the zero ofits sine wave.

The bracket 23 is provided with a flange 26 which is secured to ashoulder or boss 21 of the casing part ID by screws 28. The screws 28extend through slots 29 in the flange 26.

In one end of the casing C, I mount a shearing head S comprising anouter cutter or shearing element 30 and an inner cutter or shearingelement 3|. These are preferably formed of sheet metal, the outerelement being held stationary as by a screw 32 (see Figure 2) and theinner cutter being adapted for reciprocating movement. The shearing headS is preferably formed'of sheet metal stampings as disclosed in myco-pending application Serial No. 173,104, filed November 6, 1937 andaccordingly will not be described in furtherdetail in this application.

The armature extension 24 operatively connects with the inner. cutter 3|by extending into an opening 33 thereof and a rubber sleeve 24aeliminates noise at their particular point.

Each part l0 and l I of the casing C is provided- The block 35 isprovided with an opening 31 through which the armature extension 24extends. The opening 3'! is of such size that it will permit oscillationof the operating arm A and limit its travel with the arm engagingopposite sides of the opening as the arm swings in opposite directions.The rubber block 35 serves as a bumper for limiting motion of the armand makes the arm operate silently as there are no metal partsclattering against each other.

As an additional feature to prevent noise of the armature duringoperation, I provide a socket 38 in the core leg I! in which is mounteda second block of rubber 39. The block 39 is adapted for the armature 22to engage thereagainst so that the bending tendency of the arm A duringoperation caused by the armature 22 being attracted toward the core polel1 and resulting in vibration within the arm itself intermediate theends thereof is eliminated by the bumper 39 which damps out suchvibration thus further reducing noise. The bumper 35 also prevents thearmature from striking the poles i5, i6 and I1 during operation of themotor.

In connection with the inner cutter 3|, I provide thrust pins 40 forholding it in shearing contact with the outer cutter. Heretofore, it hasbeen customary to use springs for this purpose and the vibration set-upin the springs results in noise which I eliminate by my constructionwhich will now be described. In the block 35, sockets "ii are formed andthe thrust pins 40 are interposed between the bottoms of these socketsand the inner cutter. The pins are of such length that when the innercutter is in position in the outer cutter, the portions of the blockadjacent the bottoms of the sockets will be under slight compressionthus biasing the thrust pins toward the inner cutter. This eliminatesall metallic Springs and at the same time the single block 35 serves thedouble purpose of silencing the arm A and providing resilient shearingengagement between the cutter elements.

Throughout my structure I have provided for elimination of noise asexperienced with alternating current vibrating motors now in generaluse. The blocks 35 and 38 being made of rubber or other suitableresilient material and mounted as disclosed effectively reduce the noiseof operation to a minimum. The noise is further reduced by having thethrust pins 40 engage the block 35 and thus eliminate the necessity ofproviding metallic springs at this point in the dry shaver.

The casing part l2 can be removed by removing the three screws [3 andthereupon by using an ordinary screw driver, the screws 21 and 2! can beloosened for permitting readjustment oi the relative positions betweenthe armature and the electromagnet. This makes it possible to adjust thedevice for diflerent voltages and to secure eiiicient operation bychanging the relative positions of the parts. After such change has beenmade, the screws can be retightened for retaining the armature and corein their new positions.

Some changes may be made in the construction and arrangement of theparts of my motor without however departing from the real spirit andpurpose of my invention. 1, therefore, intend to cover by my claim, anymodified forms of structure or use of mechanical equivalents, which maybe reasonably included within their scope.

I claim as my invention:

1. An alternating current motor device for operating a driven membercomprising a casing formed in two parts having each a recess at one end,said recesses together forming a pocket when the casing is assembled, anelectromagnetic means mounted within the casing, a. vibrating arm havingone end secured to the casing, a. midportion overlying theelectromagnetic means and an operating end for said member extendingthrough said pocket outwardly from the casing, having a predeterminedamplitude of vibration at said operating end, and a block of resilientmaterial secured in said pocket having a central passage therethroughsurrounding the operating end of said arm, said passage having adimension in one direction slightly less than the amplitude of vibrationand a dimension in another direction slightly greater than the width ofsaid operating end, to permit restricted vibration or the operating armtherein, the opposite ends in said one direction providing a cushionedstop for the operating end at substantially the position of maximumamplitude of vibration and being independent of contact with saidoperating end at intermediate positions of vibration.

2. An alternating current motor device for operating a driven membercomprising a casing formed in two parts having each a recess at one end,said recesses together forming a pocket when the casing is assembled, anelectromagnetic means mounted within the casing, including a core and awinding around said core, a vibrating arm having one end secured to thecasing, a midportion overlying the electromagnetic meats and anoperating end for said member extending through said pocket outwardlyfrom the casing, having a predetermined amplitude of vibration at saidoperating end, a socket in said core adjacent the mid-portion of the armand a resilient element in the socket engaging the arm when said arm isdrawn toward the core forming thereby an intermediate cushion separatingsaid mid-portion from direct contact with the core, and a block ofresilient material secured in said Pocket having a central rectangularpassage therethrough surrounding the operating end of said arm, saidpassage having a dimension in one direction slightly less than theamplitude of vibration and a dimension in another direction slightlygreater than the width oi! said operating end, to permit restrictedvibration of the operating arm therein, the opposite ends in said onedirection providing a second cushioned stop for the arm at the operatingend at substantially the position of maximum amplitude of vibration andbeing independent of contact with said operating end at intermediatepositions of vibration.

3. In a motor driven tool, a casing, a core therein, a current coil formagnetizing said coil. an arm mounted in said casing to be attracted bysaid core when magnetized and a tool adapted to be rapidly reciprocatedby said arm, a triple cushion device for said arm comprising a bumperelement for contact with said arm to stop it in a position spaced fromcontact with said core, a resilient block mounted in said casing, saidarm extending through said resilient block, and a. resilient connectionbetween said arm and said tool comprising a sleeve of resilient materialon said arm and received in an aperature formed in the tool.

RAYMOND KNAPP.

